Syntax:
NOW([fsp])

Returns the current date and time as a value in 'YYYY-MM-DD HH:MM:SS'
or YYYYMMDDHHMMSS format, depending on whether the function is used in
a string or numeric context. The value is expressed in the current time
zone.

If the fsp argument is given to specify a fractional seconds precision
from 0 to 6, the return value includes a fractional seconds part of
that many digits.

URL: http://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html

